Electrode assembly for electron discharge devices



B. B. BROWN Jan. 4, 1949.

ELECTRODE ASSEMBLY FOR ELECTRON DISCHARGE DEVICES Filed March 8, 1944 INVENTOR Enema: 5 380W ATTORNEY Patented Jan. 4, 1949 ELECTRODE. A$SEBIBLY FOR ELECl-IRON DISCHARGE DEVICE? ltarremore B. Brown, Princeton, N. J., assignor to Radio corporation of America, a corporation of Delaware Application March a, 1944, Serial No. scans and claimed in the co-pending application of Donal et al., Serial No. 525,514, filed March; 8,

1944, and assigned to the same assi'gnee as the present application,

In one form of a magnetron utilizing cavity resonators the electrode mount. comprises an vanode block having a central opening in which a cathode is axially positioned. Radially extending slots communicating with the central opening provide the cavity resonators, the portions of the block adjacent the central opening and between the slots providing theanode segments.

In another form the cavity resonators may be bores or cy'lindrically shaped chambers extending through the anode block and parallel to: the central opening and communicating with the centralopening through slotsparallel to the axis of the central opening, the portions of the anode block adjacent the central opening and? between the slots again providing the anode segments.

In this type of magnetron it has been theusua-l practice to machine the anode bl-col: with its resonant cavities from a solid block" of conducting material such as copper; which may be inthe form of a cylinder, spaces being machined at both ends of the cylinder to provide room for mounting the cathode and cathode leads, the ends of the cylinder being closed by cover plates soldered or otherwise sealed to the ends of the cylinder to provide an envelope. In a variation, a separate anode has been formed by machining or stamping, this anode being inserted into a machined envelope in the form of a hollow cylinder, end plates again being provided to complete the envelope.

The machining of the envelope is time-con suming and the construction described; results in difiiculty in mounting and centering of the oathode.

Usually fixed magnets or'electromagnets are utilized with the magnetronsof the type: described above, Because of the long air gaps: made neces sary between the electrode mount and the -out side of the envelope larger magnets than desired are necessary to provide a field of desired intensity. In any magnetron, leads must he. em ployed to support the cathode and make contact to the cathode and the cathode heater. These leads usually pass through thespece atthe ends 9" Claims Cl. EEG-27 .55

of the anode and result in an air gap in themagnetic circuit which is inccnveniently large. lit is standard practice also to Weld a metallic disc to each end of the cathode in order to form electrostati'c shields at cathode potential at the ends of the cathode for preventing drift of' the electrons out the ends of the anode cavity. This contributes to the necessity for providing larger than desired air gaps.

It is, therefore, an object of my invention to provide an improved electron discharge device of the magnetron type using cavity resonator circuits and particularly useful at ultra high fre quencies'.

Another object of my invention is to provide such a device of simplified design which will permit ready manufacture and eliminates the need forextensive machining operations.

A still further object of my invention is to provide such a device having a novel and eiiTective means for supporting the cathode and its leads and which facilitates mounting and centering of the cathode.

More particularly it is an object of my inven tion to provide such a device in which the electrade mount assembly can. be mounted on a header to facilitate assembly of the mount and incorporation within an envelope.

A further object of my invention is to provide such a device in which the gaps in the magnetic circuit are substantially reduced, thus decreasing the size and strength of the magnet, electromagnet or coils for providing a magnetic field of required intensity.

Another object of my invention is to provide a device of the kind described, using a smaller header and envelope, and having, a large space where the internal mount structure is bolted together andmo-unting space is'needed.

A further object of my-invention is to provide an electron discharge device of the type described in which the load line may be taken from the opposite end of the envelope from the electrode leads.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims, but the invention itself will best be understood by reference to the following description taken in connection with the accompanying drawing in which Figure his; a vertical section taken along the line 1-1 of Figure 4' or an electron discharge device made accordingtomy invention, Figure 2 is a side viewwl'th portions of the envelope removed of the electron discharge device shown in Figure l,

envelope Ill having a lip ll sealed to a header member l2. The header consists of metal'ofa*- thickness sufficient to give it rigidity and for this purpose I have employed; stainles s steel A025 inches thick, the non-magnetic properties of which are of advantage in that no disturbance of the internal magnetic circuit of thetube is occasioned by its use. The envelope is also made of stainless steel. The -lip ll may be sealed to the headerbyatomic .hydrogen welding or electrioal welding, if desired. The mount includes the anode block l3 having central chamber I4 in whic h are supportedra diallydirected anode vanes or slats l5 and l5.'. the inner edges of which define a cathode chamber and provide. the anode segments, the space between the. vanes providing the cavity resona.-': tors connected between adjacent anode segments; The anode block may be secured to the header member by means of the bracket 20. v

, lnsulatingly supported from the anode block and bracket are the two non-magnetic sheet ele,-. ments I6 and H, which act as the cathode support and electron shields for preventing drift of electrons fromthe anode-cathode space. .They may be spaced close to the anode block. These non-magnetic sheets are retained on the anode. block by means of bolts [8 and I9 extending through the anode block and are insulated fromv each other, by the structure shown specifically in Figure 8. As here shown, in addition to the insulating collar members 2! and 22, the sheet' l1 may be supported in insulating relationship with coaxial line coupling device is described and claimed in the copending application of Donal and Hegbar, Serial No. 496,570, filed July 29, 1943, and assigned to the same assignee as the present application. This copending application has besome; 9 .821

Patent No. 2,44. 2,1l8,. dated May 25, In Figures S te '7 inclusive is shown the strap- -;ping method employed with an electron discharge device made according to my invention.

The purpose of such strapping is to secure the desired mode of operation, thus increasing the :i f 9 Q .-.O c tubeis asectiontaken along the line VI of Referring to Figure 6,

Figure 5, anodevane I5 is provided with a wide the inner coupling ring or strap 31 being :electrically connected to the vane as shown, all

respect to the rod by means of insulating collar.

2! and insulating washer 2ll'f. This insulatessheet I6 from sheet II. The rods lfl andJQ mayI- be insulated from the anode block by means of: the insulating collars Hand 23- The cathode 9 having a heater 9" maybe secured to and sup ported by the sheet member .l6 through v which it. extends by securing the flared end 9" to the sheet, the cathode extending axially of thechamber within the anode. One end of the cathode heater is electrically and mechanically secured to the sheetmemberlfi and the other ehdjof the heater... iselectrically and mechanically secured to. th e member I]. These sheet metal members I B and; H in turn are electricallyconnected to .conducr tors 24, and 25, inturn connected to leads Z6 and 21 sealed through the top of the envelope .;,by means of the insulating closure inember 28,

preferably of glass,which is s ealed to the extene;

sion 29 mounted at the top of the envelope,- Thus a cathode and cathode heater circuitinay be provided which is insulated from the anode block electrically connected to theheader member. v I ,Coupling loop 3ll extending through the anode block into one of, the cavity resonators is extended into an internal conductor 30' of a coaxial: line, the outer tubular conductor SI. of whicl'ris. sealed by means of cup-shaped element 3-2 or insulating material. This outer end of the cone ductor 30 acts as a radiatorwhich may be. coupled to a wave guide or cavity resonator. This device.

of the vanes indicated by the numeral I5 being electrically connected together by means of the strapping means 31. .As shown in Figure 'Lwhich is a section taken along the line .VII of Figure 5,

alternate vanes l5 are provided with slots 40- displaced with respect to the slots 39'. In this case the outeru.couplingstrap36 is electrically connected to the vanes I 5. Thus alternate anode vanes are electrically. connected together.

i: Due to the fact that'th'e anode block is mounted vertically at one end, the size of" the header is reduced over. that employed in the device dethin non-magnetic sheets used for the cathode and endshielding instead of the magnetic end inserts and the structure utilized allows the electrode leads .to be broughtout from the opposite end or the envelope from the load coupling In the final assembly ofthe tube described the fitting 29 at the top endlof theenvelope is glassed-in, leavinglan opening at thetop. The previously assembled tube structure, and the headeristhen insertedinto the envelope-the beaded heater leads 26 and 21 protrudingthrough 'the top or the glass envelope. The internal spacingsareadjusted by shims inserted through the-open top, the header and envelope assembly welded together, the shims removed and.

the glass tqpthen shrunk around the glass heater beads to sealthe envelope and complete the assemblyoi the tube. 1, 7;: 1 This form of construction has advantagesin simplicity or design, ease-oi manufacture of parts and of assembly. For any given anode block thickness the end dimensions can be easilyfixed to give the maximum efiiciency of utilization of the magneticfield which is provided by means of fixed rnagnet, for example having pole pieces 33 and 34- registering with the cathode-anode space. The envelope I0 being close to thesheets' l6 and I1, the-gaps in the magnetic circuit are made ve y smally-l While I have indicated the preferredembodimentsiof my invention of which I am now aware and havealso; indicated only one specific appli cation for. which my invention may be employed,

it will be apparentzthat my invention is by no i1 means-limited to the exact forms illustrated or the useindicated'b'ut that many variations may be-made inlthe particular "structure used and the in the appended claims.

What I claim as new is:

1. An electron discharge device having an envelope including a header member, an elec-- trode assembly mounted on said header member including an elongated anode block mounted in a direction normal to said header member and having anode elements surrounding a central space, a cathode for supplying electrons Within said space, and a sheet metal member of conducting non-magnetic material extending parallel to one surface of said anode block and insulatingly supported on said anode block and supporting said cathode.

2. An electron discharge device having an envelope including a substantially flat header member, an electrode assembly mounted on said header member and including an elongated anodeblock mounted endwise in a direction transverse to said header member and having anode elements surrounding a central space, a cathode for supplying electrons, within said central space, a first sheet metal member of conducting non-magnetic material extending parallel to one surface of said anode block and insulatingly supported on said anode block and supporting said cathode in said space, and a second sheet metal member of conducting nonmagnetic material extending parallel to the opposite surface of said anode block and insulatingly supported on said anode block and insulated from said cathode and said first sheet metal member.

3. An electron discharge device having a metal envelope including a header member of conducting material, an electrode assembly mounted on said header member including an elongated anode block mounted endwise in a direction transverse to said header member and having anode elements surrounding a central space, a cathode for supplying electrons Within said central space, means including sheet metal members of conducting non-magnetic material extending parallel to opposite surfaces of said anode block and insulatingly supported from said anode block, one of said sheet metal members supporting said cathode, said envelope having an aperture in the opposite end from said header member, and a heater for said cathode, one end of said heater being connected to one of said sheet metal members and the other end to the other of said sheet metal members, and current conducting leads extending from said sheet metal members through said aperture and sealed therein.

4. An electron discharge device having a metal envelope including a header member of conducting material, an electrode assembly mounted on said header member including an elongated anode block mounted endwise in a direction transverse to said header member and having anode elements surrounding a central space, a cathode for supplying electrons within said central space, means including sheet metal members of conducting non-magnetic material extending parallel to opposite surfaces of said anode block and insulatingly supported from said anode block, one of said sheet metal members supporting said cathode, said envelope having an aperture in the opposite end from said header member, and a heater for said cathode, one end of said heater being connected to one of said sheet metal members and the other end to the other of said sheet metal members, and current conducting leads extending from said sheet metal members through said aperture and sealed therein, said header member having an aperture and a tubular member extending from: said aperture and. a!

coupling loop extending mom, said anode block. through said tubular member and forming, therewith a coaxial line. i

5, An electron discharge device having an envelope including a flat header member, an elongated anode block supported atone end and transverse to said header member, the longitudinai axis of said block lying perpendicularly to said header member, said anode block having a central opening extending theret'hrough, a. pair of non-magnetic sheetmetal membersclose to and parallel to opposite sides of said anode block, and means on said anode block adjacent said header member insulatingly supporting said. sheet metal members on said anode: block: and, insulated from each other, said sheet: metal members being spaced further from said anode block. at said supporting means, and a cathode supported by one of said sheet metal members and: a heater for said cathode, one end oi? said heater being connected to one of said sheetmetal mem bers and the other end of said heater being connected to the other oi saidi sheet metal members, an envelope sealed tosaid header member and closely surrounding said anode block and sheet metal members and having a pair of cur rent conducting leads sealed through said envelope, each one of said leads. being connected to a different one of each of said sheet metal members, said envelope being elongated and having a flared out portion adjacent the means for insulatingly supporting said sheet: metal members.

6. An electron. discharge device including a fiat header member, an elongated anode block supported from said header member transverse to said header member, the longitudinal axisof said block lying perpendicularly to: said header member, said anode block having a central opening extending therethrough, a, pair of non-magnetic sheet metal members close to and parallel to opposite sides of said anode block, and means on said anode block adjacent said header member insulatingly supporting said sheet metal memhere on said anode block and insulated from each other, and a cathode supported by one of said sheet metal members, and a heater for said cathode, one end of said heater being connected to one of said sheet metal members and the other end of said heater being connected to the other sheet metal member, an envelope sealed to said header member and closely surrounding said anode block and sheet metal members and having a pair of current conducting leads sealed through said envelope, each one of said leads being connected to a different one of each of said sheet metal members.

'7. An electron discharge device having a metal envelope including a header member of conducting material, an electrode assembly mounted on said header member including an elongated anode block mounted endwise in a direction transverse to said header member and having anode elements surrounding a central space, a cathode for supplying electrons within said central space, means including sheet metal members of conducting non-magnetic material extending parallel to opposite surfaces of said anode block and insulatingly supported from said anode block, one of said sheet metal members supporting said cathode, said envelope having an aperture in the opposite end from said header member and a heater for said cathode, one end of said header being connected to one of said sheet metal members, and the other end to the other of velope including-a header member, an electrode assembly mounted. on said header member and including an elongated anode block mounted endwise in a direction transverse to said header member. and having anode elements surrounding a central space, a tubular cathode for supplying electrons Within said central space, a first elongated sheet metal member of conducting nonmagnetic material extending parallel to one sur face of said anode block and insulatingly supported at one end on said anode block and supporting said cathode in said space, a second sheet nietaLmember of conducting non-magnetic material extending. parallel to the opposite surface of said anode block and insulatingly supported at one end on said anode block andinsulated from said cathode and said first sheet metal member, and a heater. Within said tubular cathode and having current conducting leads extending from the opposite ends of said cathode and connected, to said insulated sheet metal members i 9. An electron discharge device having an envelope containing an electrode assembly comprising an anode block having anode segments surrounding a central space, an elongated tubular cathode for supplying electrons, in said centralspace, and means supporting said cathode in said space including a first sheet metal member extending parallel to one surface of said anode block and attached to one end of said cathode, means insulatingly mounting said first member on said anode block, a second sheet metal member extending parallel to the oppositesurface of said anode block adjacent to but spaced from the opposite end of said cathode, means insulatingly mounting said second member on said anode block, a heater disposed within said tubular cathode and having one end connected to said, cathode and said first member and the opposite.

end extending from said tubular cathode and connected to said second member, and current conducting leads extending through said envelope and connected to said two members.

BARREMORE B. BROWN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,084,867 Prinz et a1 June 22, 1937 2,147,143 Braden Feb. 14, 1939 2,410,396 Spencer Oct. 29, 1946 2,411,151 Fisk Nov. 19, 1946 FOREIGN PATENTS Number Country Date 215,600 Switzerland Oct. 16, 1941 42,290 Switzerland Jan. 15, 1938 509,102 Great Britain July 11, 1939 

